SARS‐CoV‐2 antibodies started to decline just four months after COVID‐19 infection in a paediatric population

Abstract

Aim We evaluated the prevalence of paediatric severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infections using antibody testing and characterised antibody titres by time from exposure. Methods This was a single‐centre, prospective, cross‐sectional cohort study. Patients under 18 years old were eligible to participate if they attended the paediatric emergency department at the tertiary Shaare Zedek Medical Center, Jerusalem, Israel, from 18 October 2020 to 12 January 2021 and required blood tests or intravenous access. SARS‐CoV‐2 seropositivity and antibody levels were tested by a dual‐assay model. Results The study comprised 1138 patients (56% male) with a mean age of 4.4 years (interquartile range 1.3–11.3). Anti‐SARS‐CoV‐2 antibodies were found in 10% of the patients. Seropositivity increased with age and 41% of seropositive patients had no known exposure. Children under 6 years of age had higher initial antibody levels than older children, followed by a steeper decline. The seropositivity rate did not vary during the study, despite schools re‐opening. The findings suggest that children's immunity may start falling 4 months after the initial infection. Conclusion Immunity started falling after just 4 months, and re‐opening schools did not affect infection rates. These findings could aid decisions about vaccinating paediatric populations and school closures.

A scalable and highly immunogenic virus‐like particle‐based vaccine against SARS‐CoV‐2

“…In comparison with infections with other viruses, patients infected with COVID‐19 produce neutralizing antibodies at relatively low levels 28 , 29 . Hence, we compared the total RBD‐specific IgG titers induced in mouse sera after vaccination with mCuMV TT ‐RBM to SARS‐CoV‐2 convalescent sera (total of 5 different sera).…”

“…Some studies have shown that neutralizing antibodies against SARS‐CoV‐2 are low in general and wane relatively rapidly 44 ; some patients may even completely lack long‐lasting SARS‐CoV‐2 antibodies 28 , 29 . This may be explained by coronaviruses morphological structure as they are large particles with long spike proteins resulting in RBD trimers spaced by 25 nm.…”

“…This may be explained by coronaviruses morphological structure as they are large particles with long spike proteins resulting in RBD trimers spaced by 25 nm. Other viruses and VLPs are capable of inducing optimal and long‐lived neutralizing antibodies thanks to the 180 monomers forming a repetitive surface structure with epitopes spaced by 5–10 nm 28 . The induced antibodies using mCuMV TT ‐RBM vaccine could be detected at similar levels 3 months following the booster immunization, indicating longevity of the induced response.…”

Large-scale study of antibody titer decay following BNT162b2 mRNA vaccine or SARS-CoV-2 infection

“…Combining these results with ours suggests that the recent surge in breakthrough infections in fully vaccinated individuals is due at least in part to declining levels of antibodies and not solely due to the variant strains of SARS-CoV-2. In a recent single-center, prospective, cross-sectional cohort study, children’s immunity was found to decline 4 months after the COVID-19 infection(Breuer et al, 2021). Lyer et al reported that anti-S-protein antibodies reserved neutralizing abilities and persevered for up to 75 days after SARS-CoV-2 infection in >95% of patients(Iyer et al, 2020).…”

The COVID-19 pandemic in children and young people during 2020-2021: Learning about clinical presentation, patterns of spread, viral load, diagnosis and treatment

“…Some authors detected specific IgGs 6 months after infection in children who were either asymptomatic or had mild symptoms [ 34 ]. However, other studies suggested waning of antibody responses in children 4-6 after SARS-CoV-2 infection, while parents had somewhat higher levels, but still waning [ 35 , 36 ].…”